Anti-oxidant levels in various tissues during the maturation of 'Hass' avocado (Persea americana Mill.).

摘要

Avocado is a fruit high in polyunsaturated fatty acids, with a high mineral content. However, no reports are available on how valuable avocado fruit could be as a source of anti-oxidants, depending upon their stage of maturity. Such a feature might become an important marketing tool in future. To evaluate the presence of anti-oxidant systems throughout avocado fruit development, various tissues were analysed for both their total and specific anti-oxidant compositions. Total anti-oxidant levels were found to be higher in the exocarp and in seed tissues than in the mesocarp, a possible reason for the susceptibility of avocado to post-harvest mesocarp disorders. While seed tissues contained predominantly ascorbic acid (AsA) and total phenolics (TP), the anti-oxidant composition of the mesocarp was characterised by the presence of the C7 sugar, D-mannoheptulose. Among the anti-oxidant enzymes assayed, peroxidase (POX) and catalase (CAT) were present in higher concentrations than superoxide dismutase (SOD) in mesocarp tissue. The low concentration of anti-oxidants in the mesocarp could be a major reason for the susceptibility of avocado fruit to physiological disorders.